You can stop adding fluoride to water with basically zero consequences (especially if people are already using fluoride toothpaste), whereas "pesticide residues, PFAS contamination, leachates" can't be removed without significant economic impact. Moreover, the economic impact from stopping "pesticide residues, PFAS contamination, leachates" is immediate, whereas any cavities that might show up from stopping flouride will take decades.
I found it funny how pro science the voters of Portland, OR / Multnomah County were when it came to enacting COVID protocols, but have rejected the science of water fluoridation multiple times, most recently in 2013.